Coated valving member

ABSTRACT

All areas of the butterfly type valving member which may be exposed to attach by corrosive substances, are coated with a protective material of the class of tetrafluoroethylene or equivalent substance, by a high-pressure and high-temperature molding process; the process involving withdrawing support from a journal end of the valving member during a critical phase of the molding procedure to ensure adequate coating of said journal end including the customary turning center hole thereof.

United States Patent [1 1 Walchle et al.

[ Aug. 7, 1973 COATED VALVING MEMBER [75] Inventors: David L. Walchle;Peter J. Schmidt,

both of Cincinnati, Ohio [73] Assignee: Xerox Corporation, Cincinnati,Ohio [22] Filed: Mar. 23, 1972 [21] Appl. No.: 237,583

Related US. Application Data [62] Division of Ser. No; 55,370, July 16,1970, Pat. No.

[52] US. Cl. 137/375, 251/305 [51] Fl6k 1/22 [58] Field of Search....'.137/375; 251/286, 251/305, 306

[56] I ReferencesCited UNITED STATES PATENTS 2,059,687 11/1936 Gagg251/286 8/1967 Schenck l37/375 3,394,914 7/1968 Nagasato 137/375 X3,425,439 2/1969 Duffey et al 137/375 3,450,]51 6/1969 Heutzenroeder137/375 Primary Examiner-Henry T. Klinksiek Attorney-J. Warren Kinney,Jr.

[57] ABSTRACT All areas of the butterfly type valving member which maybe exposed to attach by corrosive substances, are coated with aprotective material of the class of tetrafluoroethylene or equivalentsubstance, by a highpressure and high-temperature molding process; theprocess involving withdrawing support from a journal end of the valvingmember during a critical phase of the molding procedure to ensureadequate coating of said journal end including the customary turningcenter hole thereof.

5 Claims, 10 Drawing Figures PAIENIED SHEEI 1 0F 3 COATED VALVING MEMBERThis is a division of application, Ser. No. 055,370, filed July 16,1970, now U.S. Pat. No. 3,670,07l.

This invention relates to a coated valving member and method ofmanufacturing the same.

The valving member here concerned involves a butterfly valve or paddlevalve, which usually comprises a substantially flat circular body plateor disc of metal or other rigid material, having located at oppositeends of a diameter or chord a pair of axially aligned cylindrical shaftsections. The shaft sections may be welded, brazed, or otherwise fixedlysecured to the body plate, with the shaft section axes disposed insubstantially the mean plane of the body plate. The assembly may beconstructed of a corrosion-resistant material, preferably a metal of theclass of stainless steel, brass or bronze. If desired, the assembly maybe cast or molded as one piece.

In accordance with the present invention, the valving member is to becoated with a tough corrosion-resistant and wear-resistant materialhaving a low coefficient of friction and inherent self-lubricating,impervious properties. The coating material may be a moldable plastic ofthe class of Teflon TFE (tetrafluoroethylene), or other high densitypolyethylene, products as Teflon FEP, Kynar, Kel-F, Penton and the like.

The coating process involves high-pressure, hightemperature applicationof the coating to the body plate and to both shaft sections, withparticular attention given to fully enveloping at least one of the shaftsections. The coating is applied by injection molding procedure, andinvolves supporting the bare valving member in a mold in such manner aswill permit a flow of coating material uniformly onto all surfaces ofthe body plate and its shaft sections, including the terminal end of oneof said sections. For this purpose a novel procedure and technique areresorted to as one object of the present invention.

The coated valving member afer removal from the mold, may be mounted ina butterfly valve body which also may be plastic coated and lined, thevalve body having aligned bearings to receive and rotatably support theshaft sections of the valving member. One shaft section of the valvingmember may be disposed for manipulation, manually or mechanically, forselective disposition of the valving member to open or closed positionswithin the valve body.

An object of the present invention is to provide an improved coatedvalving member for butterfly valves, and a highly effective anddesirable method of producing such a valving member.

Another object of the invention is to minimize the cost of producing aplastic coated valving member by eliminating most or all machining ofthe valving member components.

Another object is to provide an improved coating process for valvingmembers which is highly efficient, and productive of a minimum number ofrejects in the manufacture, the coating being fully protective of allareas of the valving member which might be exposed to corrosivechemicals or gases in service.

A further object of the invention is to provide a novel method and meansof coating, whereby a shaft terminal end of the valving member may beeffectively and completely coated during the coating operation, with theassurance of maintaining uniformity of coating thickness in other areasof the valving member.

Another object is to provide a valving member of the character stated,which upon incorporation in a lined valve body, ensures easymanipulation of the valve and minimizes the likelihood of leakage of anyfluid from the interior of the valve while in service.

The foregoing and other objects are attained by the means describedherein and illustrated upon the accompanying drawings, in which:

FIG. 1 is a perspective view of a butterfly type valving member such asthe present invention is concerned with, sald valving member beinguncoated.

FIG. 2 is a view of the valving member with the plastic coating appliedthereto.

FIG. 3 is a cross-section of a mold in which is supported the valvingmember of FIG. 1 preparatory to injection of fluidic plastic into themold and about the valving member.

FIG. 4 is a view similar to FIG. 3, showing the mold charged withplastic coating material just prior to solidification of the material.

FIG. 5 is a view similar to FIG. 4, showing a phase of the moldingprocess wherein a mandrel supportive of the valving member within themold has been retracted, to permit flow of coating material into an endcavity of the valving member shaft, while partially s0- lidified coatingmaterial supports the valving member within the mold,

FIG. 6 is a cross-sectional view taken on line 6-6 of FIG. 5.

FIG. 7 is an edge view of the completed valving member.

FIG. 8 is a face view of the same.

FIG. 9 is a fragmental cross-section taken on line 9 of FIG. 8.

FIG. 10 is a fragmental cross-section taken on line 10-10 of FIG. 8.

The valving member as herein disclosed may comprise a substantialy flatcircular body plate or disc 12 of metal or other rigid material, havinglocated at opposite ends of a diameter or chord the axially alignedcylindrical shaft sections 14 and 16. The shaft section 14 mey beconsidered a stud shaft or journal adapted to rotate in a bearinglocated within a valve body. Shaft section 16 likewise is to besupported in a bearing of the valve body, and may be considered theactuating stem of the valving member.

Shaft sections 14 and 16 may be welded, brazed or otherwise fixedlysecured to body plate 12 or if desired, they may be formed integrallytherewith as by casting, molding, forging or other process. The assemblymay be constructed of a corrosion-resistant material, preferably a metalsuch as stainless steel, brass, bronze or the iike. The axes of shaftsections 14 and 16 are disposed in alignment, and may rest in the meanplane of plate 12. The journal stud 14 and a portion of stem 16 may beknurled or otherwise roughened as shown, for effecting a bond with acoating material to be applied thereto.

With further reference to FIG. 1, the outer end of stem or shank 16 maycarry a suitable head or the like 18 to receive a wrench, handle orother actuating means whereby the valving member may be rotated axiallyof members 14 and 16, either manually or by power device. Body plate 12may be provided with a center hole or through aperture 20, and with acircular row of perforations 22 spaced from the rim or perimeter of theplate. In the finished product, the perforations 20 and 22 will befilled with the plastic material which coats the valving member.

Conical hubs 24 and 26 may form the connections between the shaftsections and plate 12, and each hub may include a conical annularbearing surface denoted 28, 28 arranged concentrically with the shaftsection axes. The bearing surfaces 28, 28 are adapted to seal againstsuitable bearing surfaces of a valve body (not shown) to oppose leakageof fluid along shafts l4 and 16; however, details of this are believedunnecessary for a full understanding of the present invention. All sharpedges are to be removed from the perimeter of body plate 12, and suchedges may be rounded off, by preference.

in accordance with the present invention, the valving member is to becoated with a tough corrosion-resistant material having a lowcoefficient of friction and the qualities of imperviousness, durabilityand inherent self-lubrication. The coating material may be a mold ableplastic of the class of Teflon TFE (tetrafluor oethylene), or other highdensity polyethylene, polycarbonate, or polypropylene, and includingsuch products as Teflon FEP, Kynar, Kel-F, Penton and the like.

To apply the coating to the valving member, a bi-part metallic mold isprovided (FIGS. 3 through 6), having a first part 30 and a second part32 provided with substantially identical cavities 34 and 36, thecavities each being shaped to the outline of the valving member, withclearance all' around to accommodate the plastic material injected forenveloping the valving member. The outline of such mold cavitycorresponds substantially to the shape which results from a planebisecting the thickness of body plate 12 and shaft sections 14, 16, plusthe necessary clearance mentioned.

The mold carries a suitable clamp device 38 which grips the shaft head18 to center the shaft section 16 within the mold cavity while the moldis closed on the valving member, FIG. 3. A mandrel, which may be in theform of a pointed screw 40, may be advanced into the turning center hole42 in the stud shaft section 14, to center said shaft section 14 withinthe mold cavity according to FIG. 3. The mandrel 40 may have ascrewthreaded connection at 44 with a normally fixed bridge plate 46that spans the mold parts, said connection at 44 making possible anaxial shifting of the mandred inner end relative to shaft section 14.

Coating plastic indicated at 48, may be introduced as a heated andpressured fluid into the cavity of mold 30, 32, through a cylinder 49and sprue 50 by means of a plunger 52. The force of the plunger drivesthe fluid plastic through plate aperture 20, and laterally in alldirections over and under the valving member, until all parts of thevalving member which are exposed within the mold cavity are coated withplastic material.

Before the plastic material sets completely, but while it issufficiently stable to support the valving member against sagging withinthe mold cavity, an attendant will manipulate the mandrel 40 to retractits inner end from the turning center hole 42, thereby permitting entryof fluid plastic material into said hole. In this way, the terminal endof shaft section 14 is assured a complete cover of coating material, asis plainly indicated upon FIGS. 4, and 6. The drawing views indicatealso a complete uninterrupted coating for shaft section 16, body plate12, and the hubs 24 and 26. It is noted also that the plastic materialfills all the plate apertures and 22, FIGS. 2, 6, 8 and 9.

The plastic material may be introduced under high pressure into theheated mold at a temperature approximating 700 F, and until the moldcavity is filled and plastic material begins to exude through a smallvent located at 54. As cooling gradually occurs, the plastic material atabout 575 F, though still fluid to some extent, acquires a setsufficient to support the flat body plate 12 and stud 14 without the aidof mandrel 40; and at this stage of the process an attendant willretract the mandrel to permit flow of plastic material into the turningcenter hole 42 of the stud shaft. After cooling of the assembly to about300 F, the mold may be parted to release the coated valving memberillustrated by FIGS. 2, 7 and 8.

At the time of retracting the mandrel 40, the body plate 12 should bedisposed with its plane horizontal so as to offer maximal surface areato the partially set coating material underlying and supporting saidplate. This avoids any tendency of the body plate to cleave or shear thepartially set material. Alternatively, the mold might be disposed withthe rotating axis of the valving member upright, to the same advantage.

The reference numeral 56, FIG. 6, indicates a thermocouple or similartemperature responsive device used in measuring the mold temperature atall stages of the molding or coating procedure.

By preference, though not of necessity, the shaft sections 14 and 16 areknurled or. otherwise roughened as in FlGS. 1, 6 and 7, to enhanceadherence of the coating material and preclude any tendency thereof toslip either lengthwise or rotationally of the shaft sections. Also, thehead end B8 of shaft section 16 may remain uncoated, if desired. Withthe possible exception of head 18, all metallic surfaces of the valvingmember are protected fully by the coating of molded plastic material.The coating of molded plastic material is identified by the referencenumeral 58. As was previously pointed out, the coating material utilizedhas a high degree of durability and will effectively protect the valvingmember and its journals against thedestructive action of corrosiveliquids and gases when incorporated in a valve body.

What is claimdd is:

1. A butterfly-type valving member comprising a substantially flat,circular, substantially rigid, metal body plate, a pair of axiallyaligned cylindrical shaft sections integral with the body plate andlocated at opposite ends of a diameter or chord thereof, one of whichsections is a stud shaft having a terminal end, and the other of whichconstitutes an actuating stern having an outer end for engagement withan actuator to actuate the valve, a plurality of spaced apart openingsthrough said plate, and a protective coating material molded on saidplate, said stud shaft, and said stem, and conforming to all surfaces ofsaid plate and said stud shaft and all surfaces of said stem except saidouter end, said coating filling and extending through said openings tointegrally attach the coating on opposite sides of the plate, saidcoating material being characterized by wearresistance,corrosion-resistant and inherently selflubricating properties 2. Thevalving member as defined by claim 1, wherein said coating material is amaterial of the class of tetrafluoroethylene or the like.

3. The valving member as defined by claim 1, wherein said stud shaft andsaid stern are roughened to 5. A butterfly-type valve as in claim 1,wherein said stem includes a reduced diameter portion between the bodyplate and the-outer end of the stem defining a recessed area on thestem, said coating material filling said recess to define asubstantially flush outer surface on said stem, said coating beinginjection molded on said valve.

UNTTED STATES PATENT oTTToE CERTEFICATE OF CORRECHON Dated q st 7, 1973Patent N01.

Inventor(s) DAVID L. WALCHLE, ET. AL.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

On the cover sheet [73} "Xerox Corporation, Cincinnati,

Ohio" should read XomoxCorporation, Cincinnati, Ohio, a

corporation of Ohio Signed and-sealed this 25th day of December 1973.

(SEAL) Attest: v

EDWARD M. FLETCHER,JR. RENE D. 'I'EGTMEYER Attesting Officer ActingCommissioner of Patents ORM USCOMM-DC coma-pas U.5. GOVERNMENT PRINTINGOFFICE 2 I969 0-365'334,

1. A butterfly-type valving member comprising a substantially flat,circular, substantially rigid, metal body plate, a pair of axiallyaligned cylindrical shaft sections integral with the body plate andlocated at opposite ends of a diameter or chord thereof, one of whichsections is a stud shaft having a terminal end, and the other of whichconstitutes an actuating stem having an outer end for engagement with anactuator to actuate the valve, a plurality of spaced apart openingsthrough said plate, and a protective coating material molded on saidplate, said stud shaft, and said stem, and conforming to all surfaces ofsaid plate and said stud shaft and all surfaces of said stem except saidouter end, said coating filling and extending through said openings tointegrally attach the coating on opposite sides of the plate, saidcoating material being characterized by wearresistance,corrosion-resistant and inherently self-lubricating properties
 2. Thevalving member as defined by claim 1, wherein said coating material is amaterial of the class of tetrafluoroethylene or the like.
 3. The valvingmember as defined by claim 1, wherein said stud shaft and said stem areroughened to enhance adherence of said coating material and to opposedisplacement of said material thereon.
 4. The valving member as definedby claim 1, wherein said openings through said body plate comprise acentral aperture, and a plurality of circumferentially spaced aperturesadjacent to the periphery of said plate, all of said apertures beingfilled with the coating material.
 5. A butterfly-type valve as in claim1, wherein said stem includes a reduced diameter portion between thebody plate and the outer end of the stem defining a recessed area on thestem, said coating material filling said recess to define asubstantially flush outer surface on said stem, said coating beinginjection molded on said valve.